Sometimes even the most obvious biblical passages can be perplexing. One interesting verse is a case in point:
“Therefore, do not say, ‘What shall we eat in the seventh year, if we do not then sow or reap our crop?’ I will bestow such blessings on you in the sixth year that there will then be crop enough for three years. When you sow in the eighth year, you will continue to eat from the old crop; and even into the ninth year, when the crop comes in, you will still have the old to eat from” (Lev. 25:20-22).
It is difficult to determine how seriously the ancient Jews observed the שמיטה “Sabbatical Year” (literally “release”). The fact that people attempted to keep it at all, given the hard economic realities, is remarkable. The inhabitants of Jerusalem in the 5th cent. B.C.E. swore to let the ground remain fallow during the seventh year (Neh. 10:31). During the Maccabean revolution, the Syrian army led by general Lysias, took over the fortress of Beth-zur because food was in short supply during the sabbatical year when the attack was made. Its people “evacuated the city, because they had no provisions there to withstand a siege, since it was a sabbatical year for the land” (1 Maccabees 6:49, cf. vv. 53-54).
Josephus records that both Alexander the Great and Julius Caesar remitted Israel’s taxes during the Sabbatical years. Tactius also attests to the Jewish observance of the Sabbatical year but attributed the custom to “indolence.”
Given the animosity between Judea and Rome, the Romans demanded that the Jewish remnant of Judea continue paying the crop tax. No exceptions were made whatsoever for the struggling Jewish population of the land.
In the aftermath of the failed Bar Kochba revolution, the rabbis modified the law regarding the Sabbatical year during the Roman period to allow for food to be grown in order so that the people should survive, and be able to pay its taxes to a hostile Roman government.
What makes this an intriguing passage is the fact that the Sabbatical year continued to be observed even in a post-exilic era and most Halachic authorities ruled that the Sabbatical year was still a rabbinic obligation. The only reason the Sages exempted the farmers was because the imminent danger they faced should they have disobeyed. Other authorities insisted that it was biblically required, while others still maintained it was a nothing more than a pious custom.
Already, by the during the early part of a 3rd century Palestinian sage, Rabbi Yannai, announced what must have been a longstanding practice that the community had observed since the destruction of the Temple in Jerusalem, “Go out and sow in the seventh year, because of the arnona,” (crop tax) to aid the farmers in paying the heavy tax of the seventh year (T.B. Sanh. 26a).
 Ant. 12.378; 23.234; 14.202-206, 475; cf. Eusebius (Praep. Ev. 8.7).
“We are told that the rest of the seventh day was adopted, because this day brought with it a termination of their toils; after a while the charm of indolence beguiled them into giving up the seventh year also to inaction. But others say that it is an observance in honor of Saturn, either from the primitive elements of their faith having been transmitted from the Idזi, who are said to have shared the flight of that God, and to have founded the race, or from the circumstance that of the seven stars which rule the destinies of men Saturn moves in the highest orbit and with the mightiest power, and that many of the heavenly bodies complete their revolutions and courses in multiples of seven (Tactius, History, v, 4).
R. Abraham Ibn Daud (a.k. a. “Ra’vaad”) records that even after the destruction of the Temple, the Judean High Court counted the Jubilee years in a ceremonial manner, and sounded the shofar after Yom Kippor thus releasing their servants and returning fields to their former owners. Other medieval scholars disregard Ibn Daud’s opinion especially given the diminished status of the Jews who lived in the Holy Land after the destruction of the Temple, the census of opinion is that the Jubilee years were not even rabbinically required to be counted (Ramban, Sefer HaZechut on Gittin).
 Compare this statement with a different view found in JT, Sanh. 6:6, 21b.